Just wanted to know why...

I just wanted to know why always in the boybands world are at least 1 gay member and in the girlsbands are all straight!? Just wanted to know if somebody has a answer.. I know nobody might know it but just wondering if somebody can tell me something about it...

Gay members (ex)boybands:
Duncan James (Blue) = Bisexual
Lance ベース (NSYNC) = Gay
Mark Feehily (Westlife) = Gay

Maybe I forgot some others... :)
Yeah maybe it is a stupid 質問 but I just wanted to know :)